摘要 :
In many modern communication applications there is a need for simple circularly polarized antennas for hemispherical coverage with good axial ratio or low value of cross polarization. We revisited the crooked wire antenna becaus...
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In many modern communication applications there is a need for simple circularly polarized antennas for hemispherical coverage with good axial ratio or low value of cross polarization. We revisited the crooked wire antenna because of its simplicity. This paper presents results of our investigation on the crooked wire antennas and other elements.
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摘要 :
Recent recoil polarization measurements in Hall A at Jefferson Lab show that the ratio of the electric to magnetic form factors for the proton decreases significantly with increasing Q(sup 2). This contradicts previous Rosenbluth ...
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Recent recoil polarization measurements in Hall A at Jefferson Lab show that the ratio of the electric to magnetic form factors for the proton decreases significantly with increasing Q(sup 2). This contradicts previous Rosenbluth measurements which indicate approximate scaling of the form factors ((micro)(sub p) G(sub E)(sup p)(Q(sup 2))/G(sub M)(sup p) (Q(sup 2)) (approx) 1). The cross section measurements were reanalyzed to try and understand the source of this discrepancy. They find that the Rosenbluth measurements are consistent when normalization uncertainties are taken into account, and that the discrepancy cannot come from errors in one or two data sets. If there is a problem in the Rosenbluth data, it must be a systematic, (epsilon)-dependent uncertainty affecting several experiments.
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摘要 :
Polarized light scattering from individual particles has been analyzed todetermine the effects of particle shape. Flow cytometric techniques were used on samples of spherical microspheres and naturally occurring marine algae. An a...
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Polarized light scattering from individual particles has been analyzed todetermine the effects of particle shape. Flow cytometric techniques were used on samples of spherical microspheres and naturally occurring marine algae. An analog of the depolarization ratio was obtained by using crossed polarizers in the source and detector of the flow cytometer. Results suggest that differences between the polarized light scattering of spheres and aspherical particles are not discernible unless the scattered intensities are normalized to the forward scattering, which is roughly equivalent to particulate cross section. This research indicates that polarized light scattering, when normalized to particle size, may provide an indication of the extent of asphericity of hydrosols.
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An investigation of the cross-section for polarized neutrons scattered by amagnetic material is reported. Included in the investigation are the cross-sections for elastic (bragg), total, and inelastic scattering processes. Special...
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An investigation of the cross-section for polarized neutrons scattered by amagnetic material is reported. Included in the investigation are the cross-sections for elastic (bragg), total, and inelastic scattering processes. Special attention is paid to the information available on the chiral character of magnetic states. It is possible that the magnetic response function (also known as the spin van Hove function) is spatially anisotropic, in which case the observed signals are different for the scattering wave vectors k and -k. This situation can arise with materials in which the magnetic ions are not at centres of inversion symmetry, and when the magnetic order is not collinear, e.g. a helimagnet.
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摘要 :
Techniques for enhancing photogrammetric measurement of reflective surfaces by reducing noise were developed utilizing principles of light polarization. Signal selectivity with polarized light was also compared to signal selectivi...
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Techniques for enhancing photogrammetric measurement of reflective surfaces by reducing noise were developed utilizing principles of light polarization. Signal selectivity with polarized light was also compared to signal selectivity using chromatic filters. Combining principles of linear cross polarization and color selectivity enhanced signal-to-noise ratios by as much as 800 fold. More typical improvements with combining polarization and color selectivity were about 100 fold. We review polarization-based techniques and present experimental results comparing the performance of traditional retroreflective targeting materials, cornercube targets returning depolarized light, and color selectivity.
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摘要 :
Highlights of recent data from Jefferson Lab on the nucleon response to an electro-magnetic probe are presented. Recent technological advances in polarized beams and either polarized targets or nucleon recoil polarimeters have yie...
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Highlights of recent data from Jefferson Lab on the nucleon response to an electro-magnetic probe are presented. Recent technological advances in polarized beams and either polarized targets or nucleon recoil polarimeters have yielded a significant improvement on the precision of the data. An outlook is presented of planned experiments.
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